Radio signaling system



Sept. 8, 1%? R. D. BANGAY RADIO SIGNALING SYSTEM Filed April 2 1925INVENTOR RAYMOND D. BANGAY BY TTORNEY quired direction.

Patented Sept. 8, 1931 s OF-F lfiE RAYMOND DORR-INGTON BANGAY, 0FBRENTWOOD, ASSIGNOR TO RADIO CORPORATION OF AMERICA, A CORPORATION OFDELAWARE RADIO SIGNALING SYSTEM Application filed April 2, 1925, SerialNo. 20,033, and in Great Britain April 9, 1924.

This invention relates to a method of obtaining secrecy in radiocommunication.

According to my invention I erect two directional transmitters situatedat a suit- 5 able distance from one another and each capable ofradiating either on similar or different wave lengths a narrow beam, insome particular direction, preferably by the use of reflectors which canbe rotated to any re- The direction in which these two transmittersradiate is so arranged that the area of intersection of the two beamsoccurs at the point to which it is desired to signal. At the sendingstation, which may be at one or other of the transmitters or at someother place, means are provided for controlling both transmitters andfor distributing or splitting up the signals between the twotransmitters so that each beam carries only a portion of the signals,each portion being by itself unintelligible. It will be understood thatexcepting in the area covered by the intersection of the two beams, thesignal can only be received from one of the two transmitting stations,and, consequently these signals will not be capable of interpretationexcept in that area.

The invention is illustrated in the accompanying drawings. 7

Referring to Figure 1, a, b, are two transmitters which, as illustrated,are provided with reflectors a1, 61, whereby the narrow beamstransmitted can be caused to intersect at a receiving station 0.

As illustrated, signals are sent from a telegraph station 03 situatedbetween the transmitters a and I) throu h land lines 6, 61, by the aidof a signaling key f so arranged that the short elements or dots of theMorse code are relayed to one transmitter a or 7) while the longelements or dashes are relayed to the other transmitter.

Referring to Figure 2, which shows transmitting means which take theplace of the signaling key in Figure 1, g is a rapidly rotatingcommutator by which a signaling key f or as another alternative atelephone modulator h is sometimes connected to the. land line 0 andsometimes to the land line 61.

Referring to Figure 3, h is a telephone modulator permanently connectedto the land lines 6, 61, through filter circuits i, 111, of which 2' isdesigned to reject all frequencies below 1000 cycles for example, andaccept frequencies above this, and of which I reje'cts all frequenciesabove one thousand cycles and accepts frequencies below this.

Other methods of signaling may, however, be employed; for example, thosewhereby the marking signal is sent from one transmitter, whilst thespacing signal is sent from the other, or both transmitters may radiatecontinuously and the marking periods of the. signals be formed by twodifierent supersonic frequencies-which when combined produce a beat ofaudio-frequency; one of the component super-sonic frequencies beingimpressed on the carrier wave of one transmitter while the other isimpressed on the carrier wave of the other. In this case bothfrequencies are received simultaneously only in the area ofintersection.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I claim thefollowing 1. The method of transmitting intelligence consisting in,sending portions thereof in different directions, and radiating therespective portions directively toward a common point and assembling theportions at said point.

2. A transmission system having a sender connected by land wires toseparated directional radiating antennae which are convergently focusedupon a common receiving point.

3. A transmission system having a transmitting means, means fordissecting a message transmitted, wires for conducting the no separateelements of the dissected message to directional antennae forconvergently radiating the elements and a single receiving meansarranged to be effected by all the difa ferent elements and thus receivethe complete message.

4. In combination, means for sending oscillations, conducting meansconnected thereto, directional antennae connected to the conductingmeans whereby the position of focus of the directional antennae aloneWill determine Where all oscillations therefrom Will be received.

5. In a radio signaling system, the combination With tWo directionaltransmitters at a distance from each other and each capable of radiatinga narrow beam,of means Whereby some components of the signals are sentby one of the transmitters and other components by the othertransmitter, the paths over which the beams are radiated beingconvergent to a common point.

RAYMOND DORRINGTON BANGAY.

